The International Court of Justice has ruled in favor of Cameroon in its sovereignty dispute with Nigeria over the oil-rich Bakassi peninsula.

Thursday's court ruling at The Hague agreed that the disputed region was made part of Cameroon under a 1913 treaty between German and British colonial powers in West Africa.

At stake are major oil reserves believed to be in the border area, as well as rich fish stocks in nearby waters.

Nigeria's embassy in Paris says the verdict and its impact on Nigerian national interests are being studied.

Nigeria and Cameroon have clashed violently several times over control of the Bakassi peninsula, which was never clearly marked during colonial rule. But both nations have promised to abide by the court decision, which cannot be appealed. U.N. Secretary-General Kofi Annan called on both Cameroon and Nigeria to respect and implement the court's decision. In a statement Thursday, Mr. Annan said the United Nations is ready to help the two countries implement the court decision.

Both Nigeria and Cameroon have troops stationed near the marshy area, located in the Gulf of Guinea. Nigerian troops in the area were on high alert Thursday.

Cameroon first requested a world court ruling on the border dispute in 1994.